Talk Cancer

Question:

Authors   Fernandez E.  La Vecchia C.  D’Avanzo B.  Negri E.  Franceschi S. Institution   Institut de Salut Publica de Catalunya, Campus de Bellvitge, Universitat de   Barcelona, L’Hospitalet, Catalonia, Spain. Title   Risk factors for   colorectal cancer in subjects with family history of the   disease. Source   British Journal of Cancer.  75(9):1381-4, 1997. Abstract   The relationship between lifestyle factors, past medical   conditions, daily meal frequency, diet and the risk of   ‘familial’ colorectal cancer has been analysed using data   from a case-control study conducted in northern Italy. A total of 1584   colorectal cancer patients and 2879 control subjects were   admitted to a network of hospitals in the Greater Milan area and the   Pordenone province. The subjects included for analysis were   the 112 cases and the 108 control subjects who reported a family history of   colorectal cancer in first-degree relatives.   Colorectal cancer cases and control subjects with family   history were similarly distributed according to sex, age, marital status,   years of schooling and social class. Familial colorectal   cancer was associated with meal frequency, medical history of diabetes   (relative risk, RR = 4.6) and cholelithiasis (RR = 5.2).   Significant positive trends of increasing risk with more   frequent consumption were observed for pasta (RR = 2.5,   for the highest vs the lowest intake tertile), pastries (RR   = 2.4), red meat (RR = 2.9), canned meat (RR = 1.9), cheese (RR = 3.5) and   butter (RR = 1.9). Significant inverse associations and trends in   risk were observed for consumption of   poultry (RR = 0.4), tomatoes (RR = 0.2), peppers (RR = 0.3) and lettuce (RR =   0.3). Significant inverse trends in risk with increasing   consumption for beta-carotene and ascorbic acid were   observed (RR = 0.5 and 0.4 respectively, highest vs lowest intake tertile).   These results suggest that risk factors   for subjects with a family history of   colorectal cancer in first-degree relatives are not   appreciably different from recognized risk   factors of the disease in the general population.

Response:

Interesting study.  However, one of the problems with this kind of correlation study is that it does not elucidate the mechanisms at work. For example, it is known that vitamin E is cancer-protective by mitigating free-radical damage.  It is known that the quantity of vitamin E required to protect damage to fats increases when fat intake is increased.  So a single-variable study which shows that increased fat is correlated to increased cancer risk may really be showing that increased fat requires you to take more vitamin E to avoid an increase in cancer risk. The results in this study concerning pasta and pastries, similarly, may really be showing that Diamond and Diamond in "Fit For Life" (and Dr. Arthur Cason, who did the research that supports their claims in the 1940s or so) were right when they admonished us not to eat starchy foods in the same meal with proteins, lest we develop excessive toxicity in the digestive tract and overload our immune systems.  I.e. were the folks who ate the pasta in this study also eating protein with it? As I said, single-variable studies aren’t as informative as they could be. I wish the researchers could figure out which "better questions" to ask, and design more incisive studies to answer them.  The above two questions, i.e. joint effects of fat intake and vitamin E, and "food combining" principles, are two that I for one would like to see investigated. -John S. – Hide quoted text — Show quoted text -Authors  Fernandez E.  La Vecchia C.  D’Avanzo B.  Negri E.  Franceschi S. Institution  Institut de Salut Publica de Catalunya, Campus de Bellvitge, Universitat de  Barcelona, L’Hospitalet, Catalonia, Spain. Title  Risk factors for  colorectal cancer in subjects with family history of the  disease. Source  British Journal of Cancer.  75(9):1381-4, 1997. Abstract  The relationship between lifestyle factors, past medical  conditions, daily meal frequency, diet and the risk of  ’familial’ colorectal cancer has been analysed using data  from a case-control study conducted in northern Italy. A total of 1584  colorectal cancer patients and 2879 control subjects were  admitted to a network of hospitals in the Greater Milan area and the  Pordenone province. The subjects included for analysis were  the 112 cases and the 108 control subjects who reported a family history of  colorectal cancer in first-degree relatives.  Colorectal cancer cases and control subjects with family  history were similarly distributed according to sex, age, marital status,  years of schooling and social class. Familial colorectal  cancer was associated with meal frequency, medical history of diabetes  (relative risk, RR = 4.6) and cholelithiasis (RR = 5.2).  Significant positive trends of increasing risk with more  frequent consumption were observed for pasta (RR = 2.5,  for the highest vs the lowest intake tertile), pastries (RR  = 2.4), red meat (RR = 2.9), canned meat (RR = 1.9), cheese (RR = 3.5) and  butter (RR = 1.9). Significant inverse associations and trends in  risk were observed for consumption of  poultry (RR = 0.4), tomatoes (RR = 0.2), peppers (RR = 0.3) and lettuce (RR =  0.3). Significant inverse trends in risk with increasing  consumption for beta-carotene and ascorbic acid were  observed (RR = 0.5 and 0.4 respectively, highest vs lowest intake tertile).  These results suggest that risk factors  for subjects with a family history of  colorectal cancer in first-degree relatives are not  appreciably different from recognized risk  factors of the disease in the general population.

Response: